S7, E4: On a May evening in 1998, the seemingly idyllic marriage of a wealthy Lake Tahoe couple, Peter and Rinette Bergna, ended in a tangled crush of metal when their truck crashed through a guardrail and plunged down a mountainside. Peter miraculously escaped serious injury, but Rinette was found crushed to death. While Peter called it a tragic accident, investigators called it a brutal, premeditated crime and spent two and a half years building their case against Bergna, whom they believed was a cunning, cold-blooded killer.